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Early EVT within 6 hours linked to lower mortality, better functional outcomes versus later EVT in large vessel occlusion strokeDoes getting clot-busting treatment sooner save lives and improve recovery for stroke patients?

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Key Takeaway
Consider early EVT timing (≤6h) for lower mortality and better functional outcomes in LVO stroke, but note evidence is from a heterogeneous meta-analysis.

This meta-analysis pooled data from 18 studies, including randomized controlled trials and cohort studies, to compare outcomes of early (≤6 hours from symptom onset) versus late (>6-24 hours) endovascular thrombectomy (EVT) in patients with acute ischemic stroke due to large vessel occlusion. The primary follow-up was at 90 days.

For the main outcomes, early EVT was associated with a significantly lower 90-day mortality rate (incidence rate ratio [IRR] 0.81, p=0.0014). The absolute mortality rate was 0.66 events per person-year in the early group versus 0.77 in the late group. Functional independence, measured by the modified Rankin Scale, was more frequent with early EVT (IRR 1.22, p<0.0001), with rates of 1.72 versus 1.45 events per person-year.

The incidence of symptomatic intracranial hemorrhage (sICH) did not differ significantly between groups (IRR 0.88, p=0.33). The early group had 0.19 sICH events per person-year compared to 0.23 in the late group. Safety data on other adverse events, serious adverse events, and discontinuations were not reported.

A key limitation is the moderate to high heterogeneity across the included studies. The findings are observational and associated with timing, not causative. In practice, this evidence underscores the importance of minimizing treatment delays for EVT while supporting its continued consideration in selected patients beyond the 6-hour window.

Imagine waking up unable to move one side of your body because a major artery in your brain is blocked. This is an acute ischemic stroke. A critical question for doctors and families is how fast to act. This large review looked at patients who had this specific type of stroke caused by a large blockage. It compared those who received endovascular thrombectomy, a surgery to physically remove the clot, within six hours of symptoms versus those treated later, between six and 24 hours.

The analysis showed clear benefits for the faster group. People treated early had a significantly lower rate of death over 90 days. They were also more likely to regain their independence, meaning they could care for themselves without help. The review also checked for a serious risk: bleeding inside the brain. The data showed no significant difference in this danger between the early and late groups.

Despite these positive signs, the evidence has some important limits. The studies included were very different from one another, creating moderate to high variation in the results. This means we cannot be certain exactly how every single patient will respond. While the findings strongly suggest that minimizing treatment delays is vital, they do not replace the need for careful, individualized medical decisions.

What this means for you:
Early clot removal within six hours is linked to lower death rates and better recovery, without increasing bleeding risk.

Study Details

Study typeMeta analysis
EvidenceLevel 1
PublishedApr 2026
View Original Abstract ↓
Endovascular thrombectomy (EVT) is an established treatment for acute ischemic stroke, due to large vessel occlusion (LVO), but the optimal time window for intervention remains a subject of ongoing debate. We aimed to assess the impact of treatment timing on mortality, functional outcomes, and safety by comparing early (≤ 6 h) versus late (> 6-24 h) EVT. We conducted a systematic review and meta-analysis to evaluate the effect of time to intervention on outcomes of endovascular thrombectomy (EVT) in acute ischemic stroke. Four databases (PubMed, Web of Science, Cochrane Library, and EMBASE) were searched for studies published between 2000 and 2024. Eligible randomized controlled trials and cohort studies reported on 90-day mortality, functional outcome (modified Rankin Scale, mRS), or symptomatic intracranial hemorrhage (sICH), stratified by treatment timing (≤ 6 h vs. > 6-24 h from symptom onset). Pooled incidence rates, incidence rate differences (IRD), and incidence rate ratios (IRR) were calculated using random-effects models. Eighteen studies met inclusion criteria. The pooled incidence of symptomatic intracranial hemorrhage (sICH) was 0.19 events per person-year (95% CI: 0.12-0.26) in the early group and 0.23 events per person-year (95% CI: 0.11-0.35) in the late group, with no significant difference between groups (incidence rate difference [IRD] - 0.028; p = 0.33, incidence rate ratio [IRR] 0.88; p = 0.33). For mortality, early EVT showed a significantly lower incidence rate of 0.66 events per person-year (95% CI: 0.51-0.82) compared to 0.77 events per person-year (95% CI: 0.63-0.91) in the late EVT group (IRD - 0.148; p = 0.0012, IRR 0.81; p = 0.0014). Functional independence was more frequent in the early group (1.72; 95% CI: 1.42-2.01) than in the late group (1.45; 95% CI: 0.91-1.98) (IRD 0.32; p < 0.0001, IRR 1.22; p < 0.0001). Heterogeneity was moderate to high across outcomes. The timing of endovascular thrombectomy significantly influences clinical outcomes in acute ischemic stroke. Our analysis shows that early intervention (within 6 h) is associated with a significantly lower mortality rate and a higher likelihood of achieving functional independence at 90 days compared to late intervention (beyond 6 up to 24 h). The incidence of symptomatic intracranial hemorrhage did not differ significantly between the groups, suggesting that late treatment does not increase safety risks. These findings underscore the importance of minimizing treatment delays, while also supporting the continued use of EVT in selected patients beyond the 6-h window.
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